This invention relates to an electric contact holder base for electric lighters and for other motor vehicle gadgets, provided with a thermic protection against overheating so as to allow it to be re-utilized.
Usually in electric contact holder bases for gadgets such as lighters, the thermic protection is realized by an element of plastic material that melts in case of accidental overheating and causes the fuse to burn for short circuit. In this way, possible damage to the walls surrounding the gadget are avoided, but the case cannot be repaired, so that it necessarily has to be completely substituted.
In order to avoid having the operation of the thermic protection cause the need to substitute the whole electric holder base, other solutions propose the use of a bimetallic lamina acting as a thermic protection. This lamina is however obtained as a whole with the same springs that in the base have the function of retaining the body of a lighter or as a polarity for other gadgets; consequently, a great waste of material takes place in obtaining this substantially T shaped piece out of a bimetallic strip.
Furthermore, in said solutions, the bimetallic portion which is meant to realize the thermic protection is fitted in the inside of the base, in such a way that they are subject to accidental damage. This happens because the protection is folded back against the gadget that is inserted into the base.
Therefore, it is enough to give the gadget a slightly greater pressure than the usual in order to deform the lamina; consequently, its operation is altered or compromised. So as to avoid this eventuality, the bottom of the base is provided with an element of insulating material that raises its expense.
A purpose of this invention is to propose an electric contact holder base having a thermic protection made of a bimetallic lamina cheaper than the ones that are actually used, and in which the bimetallic lamina is located inside the base so as not to be subject to accidental crashes and deformations.
Another purpose of this invention is to propose a bimetallic lamina showing a substantially linear relation between deflection and temperature for the entire range of temperatures at which the device has to work. This prevents the temperature from reaching excessively high values inside the base and, at the same time, it allows one to obtain the base that is the object of the present invention with a simple structural arrangement, avoiding therefore working with very low tolerances when assembling the device.